Induction heating apparatus

ABSTRACT

An induction heating apparatus for heating in depth the surface of the rolls of a rolling mill including an inductor fed by an alternating current of low or medium frequency and a device permitting the rolls to rotate around their axes. The inductor comprises two end frames and two lateral conductors connecting the two end frames so as to form an inductor having two longitudinal symmetry planes which are perpendicular with respect to each other. There is also provided a device for regulating the device permitting to rotate the rolls around their axes, such regulating device being arranged so as to permit the axes of the rolls to coincide with the intersection line of the two longitudinal symmetry planes.

United States Patent [1 1 Binard et a1.

[ INDUCTION HEATING APPARATUS [75] inventors: Pierre Binard, Embourg;Joseph Trine, Oupeye, both of Belgium [73] Assignee: Elphiac, Brussels,Belgium [22] Filed: July 6, 1972 [21] Appl. No.: 269,310

[30] Foreign Application Priority Data July 8, 1971 Belgium 105624 [52]US. Cl. 2l9/10.67, 219/1057, 219/1079 [51] Int. Cl. H05b 5/18 [58] Fieldof Search 219/l0.67, 10.79,

[56] References Cited UNITED STATES' PATENTS 10/1939 Ronay 219/1067 X4/1969 Seule'n et al. 219/10.57 X 2/1964 Mucla et a1 219/1079 [451 July3, 1973 3,504,151 3/1970 Reiuke et a1 2l9/l0.67 X

Primary ExaminerJ. V. Truhe Assistant Examiner-B. A. ReynoldsAttorney-Raymond A. Robic [5 7] ABSTRACT An induction heating apparatusfor heating in depth the surface of the rolls of a rolling millincluding an inductor fed by an alternating current of low or mediumfrequency and a device permitting the rolls to rotate around their axes.The inductor comprises two end frames and two lateral conductorsconnecting the two end frames so as to form an inductor having twolongitudinal symmetry planes which are perpendicular with respect toeach other. There is also provided a device I for regulating the devicepermitting to rotate the rolls around their axes, such regulating devicebeing arranged so as to permit the axes of the rolls to coincide withthe intersection line of the two longitudinal symmetry planes. I

7 Claims, 2 Drawing Figures Patented July 3, 1973 2 Sheets-SheetPatented July 3, 1973 2 Sheets-Sheet 2 INDUCTION HEATING APPARATUS Thisinvention relates to an induction heating apparatus for heating in depththe surface of the rolls of a rolling mill, and more particularly ofrolls which are heavy and voluminous.

Induction heating apparatus for the rolls of rolling mills are known,such as, for example, an apparatus in which a roll is suspended to arotating hook or any device permitting to rotate the roll around itsaxis and in which a circular inductor is displaced longitudinally alongthe roll while the roll is rotating. The inductor of such a known deviceis fed by an alternating current of low or medium frequency. Such knownapparatus, which is relatively simple, is suitable for the rolls ofrolling mills which do not present any major handling problems.

The object of the present invention is to provide an induction heatingapparatus used for the surface heating of the rolls of a rolling millwhich are particularly voluminous and heavy, for example for the rollsthe diameter of which exceeds 1.5 meter and the length of which exceeds3 meters. However, the apparatus in accordance with the invention mayalso be used for the rolls of rolling mills which are less heavy.

The present invention is characterized in that the inductor is made oftwo end frames and of two lateral conductors interconnecting the two endframes so as to form an inductor having two lontitudinal symmetry planeswhich are perpendicular with respect to each other, and in that aregulating device is provided for regulating the position of the devicepermitting to rotate the roll around its axis, such regulating devicebeing arranged in such a manner as to permit the axis of the roll tocoincide with the line intersecting the two longitudinal symmetryplanes.

Since the rolls of a rolling mill wear out and must be turned andrehardened, the apparatus in accordance with the invention may beequipped with devices permitting to adapt itself to rolls of differentdiameters. In this respect, the lateral conductors have their ends bentat 90 and are at least temporarily mobile with respect to the end framesand connected to such end frames by their ends bent at 90.

The invention will now be disclosed with reference to a preferredembodiment thereof illustrated in the accompanying drawings in which:

FIG. 1 illustrates a perspective view, partially in secconsist of a pairof structures one unit of each pair being illustrated in the drawings.

The two supporting structures 2, only one of which is shown,'eachsupport a portion of a device permitting to rotate a roll around itsaxis. Such device consists of two levers 6 equipped with motorizedrollers 7. The position of levers 6 may be regulated by means of anappropriate control system which is illustrated schematically by ahandle 8 and a threaded shaft 9. To facilitate the transmission of thedriving power to the rollers 7, the levers 6 pivot around a rotary shaft10 driving the rollers 7 by means of chainsll only one of which isshown. The shaft 10 isdriven by a chain 12 operated by a motor 13. Thisarrangement may be identical at both ends of the roll of the rollingmill, but it is also possible to provide only one motor 13 at one end ofthe rolling mill.

The supporting structure 2 may also include a pneumatic tailstock 14 toensure perfect centering of the roll 5.

The position of the supporting structure 2 with respect to roll 5 may becontrolled by means of an appropriate control system illustrated in thedrawings by a handle 15 and a threaded shaft 16.

Around the roll of the rolling mill 5 is placed a heating inductorincluding two end frames and two longitudinal conductors. This inductoris illustrated schematically in FIG. 2. The end frames are identified byreference numeral 17 and the lateral conductors by reference numeral 18.The inductor illustrated in FIG. 2 has two longitudinal symmetry planes,a vertical plane 19 and a horizontal plane 20. In addition, there isillus trated a vertical transversal symmetry plane 21. The three planes,19, 20 and 21 are perpendicular with respect to each other. The lateralconductors 18 have ends 22 bent at 90 and the contact between theselateral conductors 18 and the end frames 17 is made at such bent ends.

In a practical embodiment of the invention, as illustrated in FIG. 1,the end frame consists of a sheet of conductors 23 bent in a U shape toconstitute a plane structure the larger surface of which isperpendicular to the axis of the roll 5. This sheet of conductors 23 isconnected by a mobile transverse member 24 which closes the U shapearrangement to form a square or a rectangle. The sheet of conductors 23rests on a base 25 secured to the mobile supporting structure 3. At itsupper portion, the sheet of conductors 23 is maintained by pneumaticclamps 26 permitting to tighten one against the other the transversemember 24 and the sheet of conductors 23. The transverse member 24 maypivot around an axis 28 secured to an upright member 29. The pivotalmovement of transverse member 24 is controlled by a pneumatic motor, notillustrated in the drawing, acting on a lever 30. During the heating ofthe roll, the transverse member 24 joins the two extremities of thesheet of conductors 23 owing to the tightening exerted by the pneumaticclamps 26.

The lateral conductors of the inductor consist of sheets of conductors31 having bent ends 32 ensuring the contact with the sheet of conductors23. The tightening of the bent ends 32 against the conductors 23 mayalso be done by means of pneumatic clamps such as clamps 26 orby meansof screws or other devices. The lateral conductors 31 may be subjectedto considerable forces because of the magnitude of the current whichflows through them. Because of that, the conductors 31 are held by aninsulating concrete slabs 33 fixed to upright members 34 strengthened bybracet members 35 secured to mobile supporting structures 4.

The mobiles supporting structures 4 may be moved perpendicularly to thelongitudinal axis of the apparatus through a device regulating theposition thereof which is not illustrated. Such a device may be a handlein a very simple case. It is important to ensure that the positioning ofthe mobile supporting structure 4 be done without hindering the symmetryof the inductor. Such symmetry does not need to be absolutely perfectbut departures therefrom are not tolerated at the locations where thelarger forces are generated, hence along conductors 31.

The conductors 23 and 31 are arranged so that water is fed through themby means of connections 36. The pneumatic clamps 26 and the pneumatictailstock 14 are connected to compressed air conduits, not illustrated,by means of connections 37.

To compensate for the heat losses through the ends of roll 5, theconductors 31 may be surrounded by magnetic field concentrators 38 madeof laminated iron and disposed adjacent to the ends of roll 5.

An alternating current generator 39, illustrated in FIG. 2 only, may beplaced on one of the mobile supporting structure 4, or each mobilesupporting structure 4 may support a current generator suitably arrangedfor a series connection.

The apparatus in accordance with the invention operates as follows:

When a roll of a rolling mill is brought towards the apparatus by meansof a rolling bridge, not illustrated, the transverse members 24 arepivoted around their axis 28 under the action of levers 30 and are thusplaced in the vertical position. The roll is placed on rollers 7 and thelevers 6 are regulated until the axis of the roll coincides with theline intersecting the longitudinal symmetry planes l9 and 20 (FIG. 2) ofthe inductor. Subsequently, the, supporting structures 4 are regulatedso as to obtain a predetermined inductive coupling with the surface ofthe roll. Finally, the roll is rotated and the heating current ispermitted to flow. The apparatus may be also equipped with means for vherdening the rolls, not illustrated, and with other auxiliary devices.The'regulation of the position may be done by means of servo-motors andof automatic measuring and controlling devices.

1. An induction heating apparatus used for the heating in 'depth of thesurface of the rolls of a rolling mill comprising an inductor fed by analternating current of low or medium frequency and including two endframes and two lateral conductors interconnecting said end frames so asto form an inductor having two longitudinal symmetry planes which areperpendicular with respect to each other, a device for rotating a rollaround its axis and means for positioning said roll rotating device insuch a way that the axis of the roll is brought in line with the lineintersecting the two longitudinal symmetry planes.

2. Apparatus as defined in claim 1, wherein said lat eral conductors arebent at 90, are at least temporarily mobile with respect to the endframes, and are connected to said end frames by their ends bent at 90.

3. An apparatus as defined in claim 2, wherein the end frames comprise aU-shaped branch and a transverse member which is temporarily mobile soas to close or open the end frame.

4. Apparatus as defined in claim 2, wherein pneumatic clamps ensurepositive contact pressure between the temporarily mobile lateralconductors and the end frames.

5. An apparatus as defined in claim 3, wherein pneumatic clamps ensu're'positive contact pressure between the temporarily-mobile transversemembers and the end frames.

6. An apparatus as defined in claim 1, wherein the device for rotatingthe roll around its axis is mounted on two first supporting structureswhich are movable longitudinally, wherein said end frames are mounted ontwo second supporting structures which are also movable longitudinally,and wherein the lateral conductors are mounted ontwo third supportingstructures movable transversally with respect to the axis of the roll.7. An apparatus as defined in claim 1, wherein levers supportingmotorized rollers are provided and constitute the device for rotatingthe'roll around its axis and wherein said levers and a devicecontrolling the position of said levers constitute themeans forpositioning said roll rotating device.

. ill t 1!

1. An induction heating apparatus used for the heating in depth of thesurface of the rolls of a rolling mill comprising an inductor fed by analternating current of low or medium frequency and including two endframes and two lateral conductors interconnecting said end frames so asto form an inductor having two longitudinal symmetry planes which areperpendicular with respect to each other, a device for rotating a rollaround its axis and means for positioning said roll rotating device insuch a way that the axis of the roll is brought in line with the lineintersecting the two longitudinal symmetry planes.
 2. Apparatus asdefined in claim 1, wherein said lateral conductors are bent at 90*, areat least temporarily mobile with respect to the end frames, and areconnected to said end frames by their ends bent at 90*.
 3. An apparatusas defined in claim 2, wherein the end frames comprise a U-shaped branchand a transverse member which is temporarily mobile so as to close oropen the end frame.
 4. Apparatus as defined in claim 2, whereinpneumatic clamps ensure positive contact pressure between thetemporarily mobile lateral conductors and the end frames.
 5. Anapparatus as defined in claim 3, wherein pneumatic clamps ensurepositive contact pressure between the temporarily mobile transversemembers and the end frames.
 6. An apparatus as defined in claim 1,wherein the device for rotating the roll around its axis is mounted ontwo first supporting structures which are movable longitudinally,wherein said end frames are mounted on two second supporting structureswhich are also movable longitudinally, and wherein the lateralconductors are mounted on two third supporting structures movabletransversally with respect to the axis of the roll.
 7. An apparatus asdefined in claim 1, wherein levers supporting motorized rollers areprovided and constitute the device for rotating the roll around its axisand wherein said levers and a device controlling the position of saidlevers constitute the means for positioning said roll rotating device.